Abeona Therapeutics Inc. announced three internally developed investigational preclinical gene therapy product candidates from its ophthalmology program. Abeona's preclinical programs are investigating the use of novel adeno-associated virus (AAV) capsids in therapies for serious genetic eye diseases. Abeona's internal research and development team developed ABO-504, which is designed to efficiently reconstitute the full-length ABCA4 gene by implementing a dual AAV vector strategy using the Cre-LoxP recombinase system.

In May 2021 at the Association for Research in Vision and Ophthalmology (ARVO) Annual Meeting, Abeona reported preclinical data demonstrating the ability of the dual AAV vector system to produce full length ABCA4 protein in cell culture. Recent proof-of-concept studies have extended these findings by showing expression of ABCA4 mRNA and full-length ABCA4 protein in the retina of subretinally dosed abca4-/- knockout mice, at levels similar to endogenous ABCA4 in wild-type animals. ABO-503, composed of a functional human RS1 packaged in the novel AIM™ capsid AAV204, has shown preclinical efficacy following delivery to the retina in a mouse model of XLRS.

Preclinical studies have demonstrated robust RS1 expression in the retina, improved cone photoreceptor density and overall photoreceptor cell survival, as well as a restoration of outer retina architecture. ABO-505 is designed to express a functional copy of human Opa1 in the retina following para-retinal injection. AB0-505 aims to take advantage of the robust optic nerve and retinal ganglion cell (RGC) transduction ability of AAV204 to deliver its genetic payload to the cells most affected by ADOA.

Preclinical studies have confirmed expression of Opa1 in both cell culture and the retinas of dosed wild-type and disease model animals. Initial efficacy results suggest an improvement in retinal signaling to the brain, and improved visual acuity in treated mutant mice.